The dual luciferase reporter gene system provides sensitive readout, while it relies on a constitutively-expressed control gene for readout normalization. However, most standard control reporter genes are not constitutively expressed under all conditions. Here, we report an effective method to construct a control reporter plasmid for the dual luciferase reporter gene system that would be suitable for hormone research in silkworm cell lines. First, we modified BmVgP78M, a stably-expressed constitutive promoter in silkworm cells by mutating its hormone-related element. Then, we constructed the pRL-VgP78M control reporter plasmid by replacing the SV40 promoter and chimeric intron sequences in pRL-SV40 with the BmVgP78M sequence. Finally, we confirmed that the pRL-VgP78M control reporter plasmid could be stably expressed in silkworm cell lines via cell transfection experiments, and it was unresponsive to the induction of ecdysone, juvenile hormone, or their transcription factors. We thus obtained a control reporter plasmid pRL-VgP78M that could be expressed stably and moderately in silkworm cells. It can be readily used as the control reporter plasmid of the dual luciferase reporter gene system for hormone research in silkworm cell lines. It will also provide a reference for construction of control reporter plasmids of dual luciferase reporter gene systems that are adaptable to cell lines isolated from other species.

ObjectiveTo investigate the efficacy and safety of camrelizumab monoclonal antibody combined with molecular-targeted therapy in elderly patients with unresectable or advanced hepatocellular carcinoma （HCC）. MethodsA retrospective analysis was performed for the patients with unresectable/advanced HCC who attended six hospitals from January 1， 2019 to March 31， 2021， and all patients received camrelizumab monoclonal antibody treatment， among whom 84.8% also received targeted therapy. According to the age of the patients， they were divided into elderly group （≥65 years） and non-elderly group （<65 years）. The two groups were assessed in terms of overall survival （OS）， progression-free survival （PFS）， objective response rate （ORR）， disease control rate （DCR）， and immune-related adverse events （irAE）. The chi-square test or the Fisher’s exact test was used for comparison of categorical data between groups； the independent samples t-test was used for comparison of normally distributed continuous data， and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups. The Kaplan-Meier method was used for survival analysis， and the log-rank test was used for comparison of survival curves. Univariate and multivariate Cox proportional hazards regression analyses were used to determine the independent influencing factors for PFS and DCR at 6 months. ResultsA total of 99 HCC patients were enrolled， with 27 in the elderly group and 72 in the non-elderly group. The elderly group had an OS rate of 67.8%， an ORR of 44.4%， and a DCR of 74.1% at 12 months and a median PFS of 6.4 （95% confidence interval ［CI］： 3.0‍ ‍—‍ ‍12.4） months， with no significant differences compared with the non-elderly group （all P>0.05）. The median OS was unavailable for the elderly group， while the non-elderly group had an OS of 18.9 （95%CI： 13.0‍ ‍—‍ ‍24.8） months； there was no significant difference between the two groups （P=0.485）. The univariate and multivariate Cox regression analyses showed that major vascular invasion （MVI） was an independent risk factor for PFS （hazard ratio ［HR］=2.603， 95%CI： 1.136‍ ‍—‍ ‍5.964， P=0.024） and DCR （HR=3.963， 95%CI： 1.671‍ ‍—‍ ‍9.397， P=0.002） at 6 months， while age， sex， etiology of HBV infection， presence of extrahepatic metastasis， Child-Pugh class B， and alpha-fetoprotein>400 ng/mL were not associated with PFS or DCR at 6 months. For the elderly group， the incidence rates of any irAE and grade 3/4 irAE were 51.9% and 25.9%， respectively， with no significant differences compared with the non-elderly group （P>0.05）， and skin disease was the most common irAE in both groups （39.4%）. ConclusionCamrelizumab monoclonal antibody combined with molecular-targeted therapy has similar efficacy and safety in patients with unresectable/advanced HCC aged ≥65 years and those aged <65 years. MVI is associated with suboptimal response to immunotherapy and poor prognosis.